American Express and The U.S. Travel Association has teamed up again to offer "Daily Getaways". One of the most notable Daily Getaway Offers I found on the website is for Marriott Gift Cards which will take place on Monday, June 9th at 1pm Eastern Time.
Use the above link to take advantage of the Marriott offer. Keep in mind that the Gift Cards are in limited quantities and will not go on sale until 1pm Eastern Time on June 9th. If you pay with American Express you get an additional 10% discount which means you can get a $1,000 Marriott Gift Card for $810, a $500 Marriott Gift Card for $405, or a $100 Marriott Gift Card for $81.
Bookmark the site and Mark your Calendars! There are also other travel deals featuring Theme Parks, and Car Rental Agencies on the website.
You are right you would loose out on the points from your Chase Marriott Card when you pay at Marriott with a gift card. If you bought the $1,000 gift card it would mean that you would loose out on a total of 5,000 Marriott points. However saving the $190 on the $1,000 Marriott Gift Card is far more valuable than the 5,000 Marriott Points you would loose from Chase. I have a Delta American Express that I plan to use to purchase one of the gift cards with that way I can earn some Delta miles since I'll loose out on the Chase Marriott Points.